The invention relates to an intake unit comprising an integrated charge air cooler for an internal combustion engine of reciprocating piston design, the engine being provided with an exhaust gas turbocharger.
EP 2 532 855 A2 discloses a heat exchanger that is attached to a housing carrying intake air, preferably an intake module. The internal combustion engine comprises a first and second coolant box, between which a finned tube block extends, wherein the tubes of the finned tube block each terminate in a base, and in each case a base is connected in sealed fashion to the respective coolant box. The first and second coolant boxes support the heat exchanger on a housing carrying the intake air, to which housing the intake module of the internal combustion engine is attached.
DE 10 2010 063 324 A1 describes a device for cooling charge air of an internal combustion engine. This device includes a plurality of second cooling tubes to transport a second coolant, wherein the first cooling tubes run along the longitudinal axis of extension of the device. A plurality of the first cooling tubes is also disposed in a perpendicular axis of extension relative to the plurality of the second coolants.
DE 10 2012 204 211 A1 discloses a charge air device for an internal combustion engine that includes a housing with a charge air cooler disposed therein. The housing, composed of plastic, includes multiple housing sections—specifically, a first housing section comprising charge air tubes, a second housing section to accommodate the charge air cooler, and a third housing section to supply air to the charge air cooler. The constructive design of the housing sections of the charge air device produces a substantial spatial expansion that conflicts with a compact configuration of said charge air cooler in an internal combustion engine having restricted installation space.
In EP 2 696 054 A1, an outboard motor in the form of an internal combustion engine comprises a machine housing having a cylinder head and a cylinder housing in which two vertical crankshafts of a crankshaft system are disposed. The crankshafts are operated through connecting rods by reciprocating pistons moving inside cylinders. The internal combustion engine is provided with a turbocharger that is attached to the top front wall of the machine housing, thereby optimizing performance and fuel consumption efficiency.
The object of the invention is to design an internal combustion engine comprising an intake unit with integrated charge air cooler that uses a specific geometric and effective constructive design, enabling the engine to be attached to an engine housing of the internal combustion engine with a minimum space requirement and that can be easily implemented. The invention must also ensure that the radiated heat from the internal combustion engine can be readily taken up by a unit container of defined strength.
This object is achieved according to the invention by an intake unit comprising an integrated charge air cooler for an internal combustion engine of the reciprocating piston design that is provided with an exhaust gas turbocharger and comprises, e.g., two cylinders accommodating reciprocating pistons, said cylinders being part of an engine housing including a cylinder housing and a cylinder head that includes two inlet ducts, to which inlet ducts the intake unit is routed by connecting ducts. The intake unit including a unit container has a first container section comprising connecting ducts, which first container section is connected to a second container section accommodating the charge air cooler, which second container section is connected to a third container section carrying the air to the charge air cooler. The internal combustion engine is in the form of an outboard engine and the engine housing includes a vertical crankshaft system and horizontal cylinders, wherein the exhaust gas turbocharger created by a turbine and a charger is disposed on a top front side of the engine housing. The first container section, the second container section, and the third container section are combined as one integrated piece to form an intake unit module composed of a light alloy, which third container section is created as a tubular body that tapers down from the second container toward the charger.
The advantages achieved by the invention are seen in the fact that the intake unit including an integrated charge air cooler can be advantageously integrated in an internal combustion engine of reciprocating piston design operating as an outboard engine, i.e., the advantages being in terms of a geometric and functional configuration or package. This is supported by the construction of the internal combustion engine that has two horizontal cylinders accommodating the reciprocating pistons. These cylinders are part of an engine housing comprising a cylinder housing and a cylinder head including inlet ducts, to which inlet ducts the intake unit is routed by connecting ducts. The intake unit, which is easy to design and provided with a unit container, exhibits an ingenious solution, which intake container is combined with the first container section supporting the connecting ducts. The first container section is connected, setting a pattern, to the second container section accommodating the charge air cooler, to which section a third container section is connected that carries the air to the charge air cooler. A vertical crankshaft system including two crankshafts and horizontal cylinders is accommodated in the engine housing of the specially designed internal combustion engine. The exhaust gas turbocharger composed of a turbine and charger is disposed in a positionally optimized manner on the top front side of the engine housing. The first container section, second container section, and third container section are combined as one integrated piece composed of a light alloy to form an intake unit module that has highly effective properties in terms of strength and the transfer of radiated heat from the internal combustion engine. In addition, the third container section proves to be an excellent technical solution, which section is created as a tubular body that tapers down from the second container section toward the charger.
Another aspect to be emphasized is that, as viewed in a horizontal plane, the first and the second container sections of the intake tube unit, on the one hand connect at the inner side with a relatively small gap to the engine housing, and on the other hand run on the outer side adjacent to a protective cover of the outboard engine. This also enables the intake unit to be employed very effectively within restricted spatial conditions in excellent fashion, such as, e.g., the conditions of an outboard engine. Another contributing factor is that the charge air cooler has a cylindrical shape to which the second container section is fitted, wherein a depth dimension of the first cylinder section approximately matches the diameter of the charge air cooler as viewed in the horizontal plane.
Outstanding design approaches involve the fact that the connecting region of the tubular body is routed to the second container section and extends by a relatively large longitudinal dimension across an essentially vertical dimension of the referenced second container section, and additionally that the body covers an air supply chamber in front of the charge air cooler by means of an enveloping section.
What is exemplary first of all here is that the connecting section of the tubular body to the second container section has approximately the shape of an ellipse that transitions through a cross-sectional change in shape into a circular end region, as viewed across the length of the tubular body. Secondly, the end region of the tubular body is routed close to the output region of the charger of the exhaust gas turbocharger, an elastic sleeve functioning between the end region of the tubular body and the output region of the charger.
Finally, an excellent technical design is achieved by the fact that the second container section includes end regions in a form analogous to drilled holes adjacent to first and second end sections of the charge air cooler, into which regions the cylinder sections of the charge air cooler project. To this end, sealing elements are provided between the end regions and the cylinder sections. The end regions are provided with recesses to accommodate the sealing elements.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.